INTEREST IN THE ATTEMPTED BIOSYNTHESIS AND ISOLATION OF TELLURIUM-CONTAINING PROTEINS HAS NECESSITATED THE DEVELOPMENT OF SYNTHETIC ROUTES FOR TELLURIUM CONTAINING AMINO ACIDS. WE CONSIDERED AN ATTRACTIVE POSSIBILITY TO BE AN ALKYL-OXYGEN CLEAVAGE OF AN APPROPRIATELY FUNCTIONALIZED BUTYROLACTONE. IT IS WELL KNOWN THAT IN THE PRESENCE OF "SOFT NUCLEOPHILES," SUCH AS THIOLATE AND SELENOLATE ANIONS, LACTONES UNDERGO EFFICIENT C-O CLEAVAGE VIA AN SN2 PROCESS. APPLICATION OF THIS REACTION TO THE RING OPENING OF A-AMINO-G-BUTYROLACTONE WITH THE "SOFT" NUCLEOPHILE, METHYL TELLUROLATE, AFFORDED TE-MET IN A ONE POT PROCESS. MORE IMPORTANTLY, FROM A BIOSYNTHETIC VIEWPOINT, THIS SYNTHETIC STRATEGY ALLOWS FOR THE CONSTRUCTION OF OPTICALLY ACTIVE L-TE-MET. TREATMENT OF THE READILY AVAILABLE HYDROCHLORIDE SALT OF RACEMIC A-AMINO-G-BUTYROLACTONE AT -78O C IN THF WITH 1.5 EQUIVALENTS OF LITHIUM METHYLTELLUROLATE IN A THF/ETHANOL/ TRIETHYLAMINE (4:1:1) SOLVENT MIXTURE (ALL DISTILLED AND DEGASSED) AT -78O C YIELDED L-TE-MET (BY TLC). USE OF TRIETHYLAMINE AND ETHANOL PROVED WERE EFFECTIVE IN SOLUBILIZING THE AMMONIUM SALT, THUS ALLOWING COMPLETE DISSOLUTION OF THE LACTONE AT -78O C. WARMING TO AMBIENT TEMPERATURE AND REMOVAL OF VOLATILES AFFORDED THE CRUDE PRODUCT. PURIFICATION WAS EFFECTED BY SOLUBILIZATION USING DEGASSED, DISTILLED, AND DEIONIZED H2O FOLLOWED BY FILTRATION AND LYOPHILIZATION TO CLEANLY AFFORD (R,S) TE-MET IN 45-50% YIELD. PURIFICATION OF RACEMIC TELLUROMETHIONINE BY ACIDIC CRYSTALLIZATION IS REPORTEDLY UNSUCCESSFUL. HOWEVER, IT WAS FOUND THAT WHEN A DEGASSED SOLUTION OF 0.1 M CITRIC ACID WAS ADDED DROPWISE TO AQUEOUS RACEMIC TE-MET UNDER AN INERT ATMOSPHERE, A CREAM-COLORED SOLID FORMED.